The dust temperature estimates of REBELS sources by [1]} are used to extrapolate from the single continuum measurements to obtain their total infrared luminosities, and infer their dust-obscured star formation rates. [2]} find that between 30% and 60% of the star formation rate in these galaxies is obscured. They find that this fraction depends on the stellar mass of the sources, similar to what is found at lower redshifts ([3]}; the fraction of dust-obscured SFR increases with stellar mass). They also use these results to quantify the contribution of dust-obscured star formation to the cosmic star formation rate density at \(z\sim 7\) . Since REBELS is not a blind, volume-limited survey, but a targeted survey, infrared luminosity functions cannot be directly directly derived. Their method involves first finding a relation between the dust luminosity and stellar mass, and then integrating across the (known) stellar mass function at \(z=7\)  ([2]}; see also, Barrufet et al., submitted). [2]} find that dust-obscured star formation at high redshifts is more important than previously assumed: it can contribute up to a third of the total cosmic SFR density at \(z\simeq 7\)  (Fig. REF ). This implies also that the cosmic SFR density does not decrease as fast as previously predicted at \(z>3\) . While there are caveats attached to this result (stellar mass and dust luminosity uncertainties, sample selection effects, etc.), it could have a profound meaning: that galaxies in the epoch of reionization already have significant amounts of dust, and indeed perhaps more dust than we were expecting to observe in such young galaxies. This in turn might challenge our understanding of how metals and dust evolve in the interstellar medium of early galaxies, as I discuss in the next section.
